I have heard from elders that on the Day of `Arafah one can make up for all of the missed prayers of that year by praying the fardh of each prayer with the intention of making up all of the missed prayers for that specific prayer (such as fajr, dhuhr, asr, etc.). This is done separate to the actual fardh prayers performed on this day.
What is the authenticity of this? Is it mentioned in any ahadith (including weak or fabricated ones)? If not, how did this act of worship originate because it seems pretty well-known around my neck of the woods (well at least amongst the laity).
remember to say:
لا إلهَ إلاّ اللّهُ وَحْـدَهُ لا شَـريكَ له، لهُ المُلـكُ ولهُ الحَمـد، وهوَ على كلّ شيءٍ قدير
La ilaha illallahu wahdahu la sharika lahu, lahul mulk wa lahul hamd, wa huwa `ala kulli sha’yin qadeer
There is no deity worthy of worship but Allah Alone. He has no partners. To Him alone belongs the Kingdom, and all praise. And He has power over all things.